This seems to be a regular question on here over the last ten years or more. It is not surprising as there are still plenty of pre-1970's houses about and flashy light fittings, often metal, are much more in vogue than the standard plastic ones of the fifties and sixties. I have just read a ten year old thread where it was true the OP was likely to put himself in danger and whilst some of the advice was sound some of it was disparaging and unhelpful.
There are a couple of points here though that the professionals don't always take into account. Not everybody earns electricians money so the glib "rewire your house" suggestion is not always an option. If you don't have the money you simply can't do it! Then there is the disruption and potentially wrecking your whole decor consideration. Often the hidden question is " I don't really understand this, I think it is dangerous but I don't have a lot of money - can you help me?" The good electricians can usually find a third way for you. For example, providing that the house wiring itself is reasonably sound it is possible to do what I have had to. Add earth to rooms where it is simple and cheap, when you can afford it, or when decorating. Elsewhere stick to plastic switches with plastic screws or screw covers. Use pendant lights and plastic fittings or class two double insulated light fittings. There are hundreds of relatively attractive and inexpensive ones available nowadays including metal ones.(Google "double insulated light fittings"). Put a notice in your fuse box stating that the lighting circuit may not be earthed. This is safe and meets the current regulations. It won't cost a fortune and may well keep you alive! Hope this helps some of the less well off who find themselves in this predicament.
There are a couple of points here though that the professionals don't always take into account. Not everybody earns electricians money so the glib "rewire your house" suggestion is not always an option. If you don't have the money you simply can't do it! Then there is the disruption and potentially wrecking your whole decor consideration. Often the hidden question is " I don't really understand this, I think it is dangerous but I don't have a lot of money - can you help me?" The good electricians can usually find a third way for you. For example, providing that the house wiring itself is reasonably sound it is possible to do what I have had to. Add earth to rooms where it is simple and cheap, when you can afford it, or when decorating. Elsewhere stick to plastic switches with plastic screws or screw covers. Use pendant lights and plastic fittings or class two double insulated light fittings. There are hundreds of relatively attractive and inexpensive ones available nowadays including metal ones.(Google "double insulated light fittings"). Put a notice in your fuse box stating that the lighting circuit may not be earthed. This is safe and meets the current regulations. It won't cost a fortune and may well keep you alive! Hope this helps some of the less well off who find themselves in this predicament.